Ageratina altissima (L.) King & H.E. Robins. var. roanensis (Small) Clewell & Wooten

Locations ofAgeratina altissima (L.) King & H.E. Robins. var. roanensis (Small) Clewell & Wooten in Virginia

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Botanical Name
Ageratina altissima (L.) King & H.E. Robins. var. roanensis (Small) Clewell & Wooten
Common Name
Appalachian White Snakeroot
Eupatorium rugosum Houtt. var. roanensis (Small) Fernald
Flora of Virginia Name/Status
Ageratina altissima (L.) King & H.E. Robins. var roanensis (Small) Clewell & Wooten
Var. roanensis represents plants of the Southern Appalachians that are generally larger in all dimensions and have longer involucral bracts with long, cuspidate apices. See Clewell & Wooten, 1971 (Brittonia 23:123-143). Outside the Southern Blue Ridge, plants with intermediate characters that are not easily identifiable to variety have been noted (see Habitat notes). Pending further investigation, this taxon is mapped only in counties from which confirmed specimens have been collected.
High-elevation forests, especially cove forests and northern hardwood forests; also on balds. Locally common in the sw. mountains. Unequivocal Ageratina altissima var. roanensis is known only from higher elevations of the Southern Blue Ridge, especially the Balsam Mountains in Grayson, Smyth, and Washington counties, where it is common. However, it has been attributed by various sources to counties in the Ridge and Valley and the Northern Blue Ridge, ranging to nw. Virginia. Some of these reports may be referable to large plants of var. altissima that approach var. roanensis in certain characters (see comments), but whether this taxon occurs outside the Southern Blue Ridge needs further investigation.
Native Status

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